Arc welding operations are known to produce undesirable fumes and smoke during the welding process, many of which are particularly noxious to the welder or others in the vicinity of the welding operation. Such fumes and smoke when allowed to accumulate in confined spaces have long been known to constitute a safety hazard, as well as an interference to welder visibility and general welding operation efficiency.
Fume extraction devices commonly have been employed to remove the fumes and smoke from the welding area to overcome the above-noted difficulties. Such devices comprise a dual conduit, with one conduit containing the conventional components of the welding apparatus and the other conduit providing a passageway for extraction of the undesirable fumes. The conduits may be formed concentrically.
Representative prior art patents describing such fume-extracting welding process includes:
U.S. Pat. Nos.
3,909,586, 4,016,398, 2,768,278, 4,057,705, 3,305,664, 4,095,080, 3,514,567, 4,276,464, 3,707,616, 4,284,873, 3,775,587, 4,340,804, 3,878,354, 4,382,170, 3,886,344, 3,980,860.
Canada
954,786,
West German Patent No.
3,135,381
U.S. Pat. Nos.
1,981,570, 4,388,514, 3,186,132, 4,493,970, 3,524,038, 4,502,179, 4,168,562, 4,527,037, 4,183,116, 4,565,914, 4,287,405, 4,797,528, 4,330,109,
West German Patent Nos. 2,948,475 and 3,421,202. Of this prior art, it is believed that the structure shown in U.S. Pat. No. 3,909,586 and West German Patent no. 3,135,381 are the closest known art to the present invention. Both of these patents describe fume extracting welding guns in commercial use. The former patent does not use shielding gas while latter does.